1. An exclamation used to express annoyance, frustration, or surprise; a mild oath.
Usage: informal; euphemistic substitute for 'damnation'

1. The state of being damned; damnation (archaic or dialectal usage).
Usage: archaic; rare

Examples

• Darnation! I forgot my keys again.
• Well, I'll be darnation—that's the third time this week.
• Darnation, this computer is running so slowly.
• What in darnation is going on here?
• Oh darnation, I spilled coffee all over my shirt.